The present invention relates to therapeutic pharmaceutical compositions comprising an effective amount of a pyrimidine derivative in combination with an effective amount of camptothecin or camptothecin derivatives, which are useful for the treatment of cancer.
The invention relates to the treatment of cancer, especially solid tumors, with associations of camptothecin derivatives and other anticancer drugs and the use of such associations for an improved treatment.
More specifically, the invention relates to anticancer treatments with associations of camptothecin derivatives such as irinotecan (CPT-11; Camptosar(copyright)), topotecan, 9-aminocamptothecin and 9-nitrocamptothecin and a pyrimidine derivative. Pyrimidine derivatives include uracil, thymine, cytosine, methylcytosine and thiamine containing compounds. Examples of such pyrimidine derivatives are capecitabine, gemcitabine and multi-targeted antifolate (MTA), also known as pemetrexed.
European patent EP 137,145, incorporated herein, describes camptothecin derivatives of the formula: 
in which, in particular, R1 is hydrogen, halogen or alkyl, X is a chlorine atom or NR2R3 in which R2 and R3, which may be identical or different, may represent a hydrogen atom, an optionally substituted alkyl radical, a carbocycle or a heterocycle which are optionally substituted, or alkyl radicals (optionally substituted) forming, with the nitrogen atom to which they are attached, a heterocycle optionally containing another hetero atom chosen from O, S and/or NR4, R4 being a hydrogen atom or an alkyl radical and in which the group Xxe2x80x94COxe2x80x94Oxe2x80x94 is located in position 9, 10 or 11 on ring A.
These camptothecin derivatives are anticancer agents which inhibit topoisomerase I, among which irinotecan, in which Xxe2x80x94COxe2x80x94Oxe2x80x94 is [4xe2x80x94(1-piperidino-1-piperidino]carbonyloxy, is an active principle which is particularly effective in treatment of solid tumors, and in particular, colorectal cancer.
The European patent application EP 74,256 also describes other camptothecin derivatives which are also mentioned as anticancer agents, in particular, derivatives of a structure analogous to the structure given above and in which Xxe2x80x94COxe2x80x94Oxe2x80x94 is replaced with a radical xe2x80x94Xxe2x80x2Rxe2x80x2 for which Xxe2x80x2 is O or S and Rxe2x80x2 is a hydrogen atom or an alkyl or acyl radical.
Other camptothecin derivatives have also been described, for example, in the patents or patent applications EP 56,692, EP 88,642, EP 296,612, EP 321,122, EP 325,247, EP 540,099, EP 737,686, WO 90/03169, WO 96/37496, WO 96/38146, WO 96/38449, WO 97/00876, U.S. Pat. No. 7,104,894, JP 57 116,015, JP 57 116,074, JP 59 005,188, JP 60 019,790, JP 01 249,777, JP 01 246,287 and JP 91 12070 or in Canc. Res., 38 (1997) Abst. 1526 or 95 (San Diegoxe2x80x9412-16 April), Canc. Res., 55(3):603-609(1995) or AFMC Int. Med. Chem. Symp. (1997) Abst. PB-55 (Seoulxe2x80x9427 July-1 August).
Camptothecin derivatives are usually administered by injection, more particularly intravenously in the form of a sterile solution or an emulsion. Camptothecin derivatives, however, can also be administered orally, in the form of solid or liquid compositions.
CPT-11 is one of the most active new agents in colorectal cancer. Colorectal cancer is a leading cause of morbidity and mortality with about 300,000 new cases and 200,000 deaths in Europe and the USA each year (See P. Boyle, Some Recent Developments in the Epidemiology of Colorectal Cancer, pages 19-34 in Management of Colorectal Cancer, Bleiberg H., Rougier P., Wilke H. J., eds, (Martin Dunitz, London 1998); andxe2x80x94Midgley R. S., Kerr D. J., Systemic Adjuvant Chemotherapy for Colorectal Cancer, pages 126-27 in Management of Colorectal Cancer, Bleiberg H., Rougier P., Wilke H. J., eds, (Martin Dunitz, London 1998).) Although about fifty percent of patients are cured by surgery alone, the other half will eventually die due to metastatic disease, which includes approximately 25% of patients who have evidence of metastases at time of diagnosis.
In colorectal cancer patients resistant to 5-FU, single agent CPT-11 tested in two large phase III randomized trials resulted in a longer survival and a better quality of life compared with supportive care only (D. Cunningham, S. Pyrhxc3x6nen, R D. James et al, The Lancet, 352 (9138):1413-1418 (1998)) and also in a longer survival without deterioration in quality of life compared with 5-FU/FA best infusional regimens (P. Rougier, E. van Cutsem et al; The Lancet, 352 (9138):1407-1418 (1998)). CPT-11 is therefore the reference treatment in metastatic colorectal cancer (MCRC) after failure on prior 5-FU treatment.
CPT-11 has also been shown to be at least as active as the so-called standard 5-FU/FA bolus in chemotherapy naive patients with MCRC [Proc. Am. Soc. Clin. Oncol., vol 13 (1994), (Abstr. #573); J. Clin Oncol, 14(3):709-715 (1996); J. Clin Oncol, 15(1):251-260 (1997).
Combinations of irinotecan (CPT-11) and 5-FU have already been studied in phase I studies in Japan, indicating in preliminary results that concurrent administration is feasible in terms of safety (L. Saltz et al., Eur. J. Cancer 32A, suppl 3:S24-31 (1996))
A study relating to CPT-11 published by D. Cunningham, Eur. J. Cancer, 32A suppl. 3:S1-8 (1996) concluded that CPT-11 offers a different cytotoxic approach that may complement the use of 5-FU/folinic acid in colorectal cancer.
To demonstrate the efficacy of a combination, it may be necessary to compare the maximum tolerated dose of the combination with the maximum tolerated dose of each of the separate constituents in the study in question. This efficacy may be quantified, for example by the log10 cells killed, which is determined by the following formula:
log10 cell killed=T-C(days)/3.32xc3x97Td 
in which T-C represents the time taken for the cells to grow, which is the mean time in days for the tumors of the treated group (T) and the tumors of the treated group (C) to have reached a predetermined value (1 g for example), and Td represents the time in days needed for the volume of the tumor in the control animals (T. H. Corbett et al., Cancer, 40, 2660.2680 (1977); F. M. Schabel et al., Cancer Drug Development, Part B, Methods in Cancer Research, 17, 3-51, New York, Academic Press Inc. (1979)). A product is considered to be active if the log10 cell kill is greater than or equal to 0.7. A product is considered to be very active is the log10 cell kill is greater than 2.8.
The efficacy of a combination may also be demonstrated by determination of the therapeutic synergy. A combination manifests therapeutic synergy if it is therapeutically superior to one or the other of the constituents used at its optimum dose (T. H. Corbett et al., Cancer Treatment Reports, 66, 1187 (1982)).
It has now been found that the combination of camptothecin derivatives with pyrimidine derivatives is especially effective in the treatment of solid tumors, such as ovarian, NSCLC and colorectal cancer. Among the effective pyrimidine derivatives are gemcitabine, MTA, and capecitabine.
Gemcitabine exhibits antitumor activity. The salt of gemcitabine, 2xe2x80x2-deoxy-2xe2x80x2,2xe2x80x2-difluorocytidine monohydrochloride, is provided for clinical use as an intravenous solution for treatment of solid tumors such as non-small cell lung cancer (NSCLC).
Gemcitabine exhibits cells phase specificity, primarily killing cells undergoing DNA synthesis (S-phase) and also blocking the progression of cells through the G1/S-phase boundary. Gemcitabine is metabolized intracellularly by nucleoside kinases to the active diphosphate (dFdCDP) and triphosphate (dFdCTP) nucleosides. The cytotoxic effect of gemcitabine is attributed to a combination of two actions of the diphosphate and the triphosphate nucleosides, which leads to inhibition of DNA synthesis. First, gemcitabine diphosphate inhibits ribonucleotide reductase, which is responsible for catalyzing the reactions that generate the deoxynucleoside triphosphates for DNA synthesis. Inhibition of this enzyme by the diphosphate nucleoside causes a reduction in the concentrations of deoxynucleotides, including dCTP. Second, gemcitabine triphosphate competes with dCTP for incorporation into DNA. The reduction in the intracellular concentration of dCTP (by the action of the diphosphate) enhances the incorporation of gemcitabine triphosphate into DNA (self-potentiation). After the gemcitabine nucleotide is incorporated into DNA, only one additional nucleotide is incorporated into DNA. After this addition, there is inhibition of further DNA synthesis.
Gemcitabine has shown promise in combination with CPT-11 as a treatment for pancreatic cancer in Phase II studies.
MTA (multi-targeted antifolate) is an antimetabolite which is a folate antagonist, dihydrofolate reductase inhibitor and thymidylate synthase inhibitor. It is provided for use as an intravenous solution and has been found to inhibit tumor growth in mice. It is currently being tested in humans for treatment of non-small lung cancer, mesothelioma, melanoma, bladder cancer, breast cancer, pancreatic cancer, colorectal cancer, and other solid tumors.
Capecitabine is a fluoropyrimidine carbamate with antineoplastic activity. It is an orally administered prodrug of 5xe2x80x2-deoxy-5-fluorouridine (5xe2x80x2-DFUR) which is converted to 5-fluorouracil in the body. In preclinical studies, capecitabine has demonstrated activity in colorectal, breast, and head and neck carcinomas, including those resistant to 5-FU.
The chemical name for capecitabine is 5xe2x80x2-deoxy-5-fluoro-N-[(pentyloxy)-carbonyl]-cytidine and it has a molecular weight of 359.35. Capecitabine has the following structural formula: 
Capecitabine has a unique mechanism of activation that exploits the high concentrations of the enzyme thymidine phosphorylase in tumor tissue compared with healthy tissue, leading to tumor-selective generation of 5-FU.
Two randomized, phase III studies have shown that oral capecitabine is an effective first-line therapy for metastatic colorectal cancer, achieving a superior response rate and at least equivalent survival and time to disease progression compared with intravenous (i.v.) 5-FU/leucovorin (Mayo Clinic regimen). Capecitabine also demonstrated a more favourable safety profile compared with the Mayo Clinic regimen.
The present invention is illustrated, but not limited, by the examples below.